Reproducibility of SERS substrates based on gold colloids is still an open issue due to the very many different variables which affect their growth and their long-term stability. The main causes of colloids instability are related to changes in the nanoparticle dimensions and on their tendency to aggregation. In this work a seedless recipe for the synthesis of Gold Nanorod colloids was adopted and the evolution of the colloidal suspension was studied through UV-Vis spectroscopy in long-term tests (up to one month). Factors such as vacuum and air environment, shielding effect promoted by NaCl solution, dissolution in water, pure colloid state and de-aerated water were used to evaluate their correlation to colloid aggregation parameters and their influence on longitudinal and transverse plasmon bands as well as nanorods and nano-ellipses dimensions.
La riproducibilità dei substrati SERS a base di colloidi d'oro è ad oggi un problema aperto a causa delle numerose variabili che possono modificare le condizioni di crescita e la loro stabilità a lungo termine. Le cause principali dell’instabilità dei colloidi sono legate a variazioni dimensionali delle nanoparticelle e alla loro tendenza all’aggregazione. In questo lavoro si è adottata una ricetta “seedless” per la sintesi dei nanorods d’oro e si è poi studiata tramite spettroscopia UV-Vis la loro evoluzione temporale (fino a un mese). Fattori quali lavorare in vuoto o in condizioni ambientali, l'effetto di schermatura promosso da soluzioni di NaCl, la dissoluzione in acqua, lo stato colloidale puro e l’uso di acqua de-aerata sono stati considerati per valutare la loro correlazione con i parametri di aggregazione e la loro influenza sulla posizione delle bande plasmoniche di assorbimento longitudinali e trasversali, nonché sulle dimensioni dei nanorods e delle nano-ellissi.
Synthesis of gold nanorods : an exploratory study of stability conditions
BERTUOL PIETRESKI, LORI ANGELA
2020/2021
Abstract
Reproducibility of SERS substrates based on gold colloids is still an open issue due to the very many different variables which affect their growth and their long-term stability. The main causes of colloids instability are related to changes in the nanoparticle dimensions and on their tendency to aggregation. In this work a seedless recipe for the synthesis of Gold Nanorod colloids was adopted and the evolution of the colloidal suspension was studied through UV-Vis spectroscopy in long-term tests (up to one month). Factors such as vacuum and air environment, shielding effect promoted by NaCl solution, dissolution in water, pure colloid state and de-aerated water were used to evaluate their correlation to colloid aggregation parameters and their influence on longitudinal and transverse plasmon bands as well as nanorods and nano-ellipses dimensions.File | Dimensione | Formato | |
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2021_April_Bertuol_Pietreski.pdf
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Descrizione: Synthesis of Gold Nanorods: an exploratory study of stability conditions
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https://hdl.handle.net/10589/174070